From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-alma10-1.taild15c8.ts.net [100.103.45.18]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 9D05927280A for ; Fri, 31 Jul 2026 20:58:49 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=100.103.45.18 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1785531531; cv=none; b=KFHcOxk1HsdOQBwHR7xKjpPnyUFVADjvq6Sjvm3YEs2ZXFlOU8byH2/r3Btss0133OsTq5vyR/duceORJs1SCDuTGyx9lwA4LxCr0mM+2owlMayjacTeESV3T4sB7p4JZBawoqI7SlPNRa+I4eZy515atVrK3QE29/PjZF6nT4U= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1785531531; c=relaxed/simple; bh=Yw2nClG5Ej20phicbZS1T0tgbICQMND/unskqcrL9WU=; h=Date:To:From:Subject:Message-Id; b=UUVQXaWEy9rvuugb7vmWrND6gKvANKxMKI/1+qxkLwjhUAhtf8xbJYX088taR4gp5dizN9x6y81tnhXpqlAg/AJSdZmCk25QzdADWrrpPIybTw0iNMgBFArK9Yul3BsleRgEFT0DUzaIFQajh6D8bvF+LnJjOBZ7z/xKKqA1OKQ= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linux-foundation.org header.i=@linux-foundation.org header.b=mICR/sqo; arc=none smtp.client-ip=100.103.45.18 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linux-foundation.org header.i=@linux-foundation.org header.b="mICR/sqo" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 114271F00AC4; Fri, 31 Jul 2026 20:58:49 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linux-foundation.org; s=korg; t=1785531529; bh=fczO+ysEhZvvNr4BCEc24fkNLgzw5Eow4f2KnQ01ab8=; h=Date:To:From:Subject; b=mICR/sqoYYpdPhCCQCD6EedDhUw9arD5LSJjzNzD1DwQnuxeFV1CAUz/KrBKRDZfw kMEQq0+ef9mRGxZb4lK5YzrWpo+hDwJNhjK61uViEmoCriKNQl4V8TZcMp1ZbOJGNq 3UEasc+oj79drsvxlcHg7IEv13s5dhc+OplJ0DhU= Date: Fri, 31 Jul 2026 13:58:48 -0700 To: mm-commits@vger.kernel.org,willy@infradead.org,william.kucharski@oracle.com,ryan.roberts@arm.com,ljs@kernel.org,liam@infradead.org,lance.yang@linux.dev,hannes@cmpxchg.org,dev.jain@arm.com,david@kernel.org,baolin.wang@linux.alibaba.com,baohua@kernel.org,ziy@nvidia.com,akpm@linux-foundation.org From: Andrew Morton Subject: + mm-huge_memory-use-folios-memcg-inside-__folio_split.patch added to mm-new branch Message-Id: <20260731205849.114271F00AC4@smtp.kernel.org> Precedence: bulk X-Mailing-List: mm-commits@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: The patch titled Subject: mm/huge_memory: use folio's memcg inside __folio_split() has been added to the -mm mm-new branch. Its filename is mm-huge_memory-use-folios-memcg-inside-__folio_split.patch This patch will shortly appear at https://git.kernel.org/pub/scm/linux/kernel/git/akpm/25-new.git/tree/patches/mm-huge_memory-use-folios-memcg-inside-__folio_split.patch This patch will later appear in the mm-new branch at git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm Note, mm-new is a provisional staging ground for work-in-progress patches, and acceptance into mm-new is a notification for others take notice and to finish up reviews. Please do not hesitate to respond to review feedback and post updated versions to replace or incrementally fixup patches in mm-new. The mm-new branch of mm.git is not included in linux-next If a few days of testing in mm-new is successful, the patch will me moved into mm.git's mm-unstable branch, which is included in linux-next Before you just go and hit "reply", please: a) Consider who else should be cc'ed b) Prefer to cc a suitable mailing list as well c) Ideally: find the original patch on the mailing list and do a reply-to-all to that, adding suitable additional cc's *** Remember to use Documentation/process/submit-checklist.rst when testing your code *** The -mm tree is included into linux-next via various branches at git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm and is updated there most days ------------------------------------------------------ From: Zi Yan Subject: mm/huge_memory: use folio's memcg inside __folio_split() Date: Thu, 30 Jul 2026 22:18:00 -0400 Patch series "Honor XA_FLAGS_ACCOUNT in xas_split_alloc() and charge to folio's memcg", v2. __GFP_ACCOUNT is needed for xarray node allocation accounting when XA_FLAGS_ACCOUNT is set. Commit 7b785645e8f13 ("mm: fix page cache convergence regression") fixed a workingset regression with it. xas_split_alloc() does not have it and needs to be fixed. In addition, based on Sashiko's review[1] and Johannes' confirmation[2], to charge the right memcg, folio's memcg needs to be active during folio split. Add that before adding __GFP_ACCOUNT. There is no workingset convergence regression related to missing __GFP_ACCOUNT in xas_split_alloc() and the impact to userspace should be minor. During a pagecache folio split, an xarray node allocation can happen and needs to charge at folio's memcg instead of folio split invoker's memcg, because for example folio split can happen during reclaim and reclaim's active memcg might not be folio's memcg. Switch to folio's memcg at the beginning and switch back afterwards. Link: https://lore.kernel.org/20260730-add-gfp_account-to-xas_split_alloc-v2-0-5a56c2361d85@nvidia.com Link: https://lore.kernel.org/20260730-add-gfp_account-to-xas_split_alloc-v2-1-5a56c2361d85@nvidia.com Link: https://sashiko.dev/#/patchset/20260727-add-gfp_account-to-xas_split_alloc-v1-1-9fae6bf64838%40nvidia.com?part=1 [1] Link: https://lore.kernel.org/all/amtcBZ-_QVRgCd6b@cmpxchg.org/ [2] Fixes: 6b24ca4a1a8d4 ("mm: Use multi-index entries in the page cache") Signed-off-by: Zi Yan Suggested-by: Johannes Weiner Cc: Baolin Wang Cc: Barry Song Cc: David Hildenbrand Cc: Dev Jain Cc: Lance Yang Cc: Liam R. Howlett Cc: Lorenzo Stoakes Cc: Matthew Wilcox (Oracle) Cc: Ryan Roberts Cc: William Kucharski Signed-off-by: Andrew Morton --- mm/huge_memory.c | 20 ++++++++++++++++---- 1 file changed, 16 insertions(+), 4 deletions(-) --- a/mm/huge_memory.c~mm-huge_memory-use-folios-memcg-inside-__folio_split +++ a/mm/huge_memory.c @@ -4106,34 +4106,42 @@ static int __folio_split(struct folio *f XA_STATE(xas, &folio->mapping->i_pages, folio->index); struct folio *end_folio = folio_next(folio); bool is_anon = folio_test_anon(folio); + struct mem_cgroup *memcg, *old_memcg; struct address_space *mapping = NULL; struct anon_vma *anon_vma = NULL; int old_order = folio_order(folio); struct folio *new_folio, *next; int nr_shmem_dropped = 0; enum ttu_flags ttu_flags = 0; - int ret; pgoff_t end = 0; + int ret; VM_WARN_ON_ONCE_FOLIO(!folio_test_locked(folio), folio); VM_WARN_ON_ONCE_FOLIO(!folio_test_large(folio), folio); if (folio != page_folio(split_at) || folio != page_folio(lock_at)) { ret = -EINVAL; - goto out; + goto out_no_memcg; } if (new_order >= old_order) { ret = -EINVAL; - goto out; + goto out_no_memcg; } ret = folio_check_splittable(folio, new_order, split_type); if (ret) { VM_WARN_ONCE(ret == -EINVAL, "Tried to split an unsplittable folio"); - goto out; + goto out_no_memcg; } + /* + * switch to folio's memcg as xarray node allocation can happen and + * needs to charge to it. + */ + memcg = get_mem_cgroup_from_folio(folio); + old_memcg = set_active_memcg(memcg); + if (is_anon) { /* * The caller does not necessarily hold an mmap_lock that would @@ -4276,6 +4284,10 @@ out_unlock: if (mapping) i_mmap_unlock_read(mapping); out: + /* restore to caller's old_memcg */ + set_active_memcg(old_memcg); + mem_cgroup_put(memcg); +out_no_memcg: xas_destroy(&xas); if (is_pmd_order(old_order)) count_vm_event(!ret ? THP_SPLIT_PAGE : THP_SPLIT_PAGE_FAILED); _ Patches currently in -mm which might be from ziy@nvidia.com are mm-percpu-km-clear-page-private-before-free-them.patch mm-compaction-stop-recording-free-page-order-in-page-private.patch mm-huge_memory-add-page-private-check-back-in-__split_folio_to_order.patch mm-page_alloc-make-sure-tail_page-private-is-zero-at-page-free-time.patch mm-page_alloc-remove-set_page_private-in-prep_compound_tail.patch mm-huge_memory-use-folios-memcg-inside-__folio_split.patch xarray-honor-xa_flags_account-in-xas_split_alloc.patch